JPS61230101A - Color filter - Google Patents

Abstract

PURPOSE:To make the whole filter bright without any deterioration in light resistance by providing a transparent part between colored part which are arrayed in a fine and regular shape so that its area is 10-50% of the total area of the colored parts. CONSTITUTION:A red pattern 1, a green pattern 2, and a blue pattern 3 are arrayed on a transparent organic film in a fine and regular shape, e.g. square and the area of transparent parts 18 of patterns is 10-50% of the total area of the colored parts. This color filter is incorporated in a TFT liquid-crystal display and the patterns 1, 2, and 3 are formed in the same of transparent picture element electrodes 6 and every transparent part 18 is arranged between a source line 4 and a transistor part 19, so that white light transmitted through the transparent parts 18 make the filter bright. Thus, the whole filter is made bright without any deterioration in light resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to the structure of a color filter formed by coloring a transparent organic film with a dye.

[Summary of the invention]

The present invention makes the entire filter brighter without deteriorating its light resistance by providing a transparent or semi-transparent part on a color filter colored with aIII.

[Conventional technology]

Color filters, which are transparent organic films colored with dyes, are used in a wide variety of fields because they are relatively inexpensive and have excellent optical properties. For example, single-colored gelatin filters are widely used in the photographic and video fields of cameras, videos, etc. for the purpose of one-color correction and cutting of infrared, ultraviolet, or visible light.

It is formed on a transparent substrate such as gelatin, casein, or Greeny in the form of organic gt line stripes or II'i squares (hereinafter referred to as patterns) on a transparent substrate such as magenta or glass, and dyes are used to form red, green, and blue. So-called dyeing color filters, which are regularly dyed into the three primary colors of light, are often used together with interference filters as color separation filters in color imaging devices.

Furthermore, i! #In recent years, this dyeing method color filter has been combined with the progress of liquid crystal displays, and has been applied as a liquid crystal pull color display.69. It has been put into practical use and is becoming widespread.

This dyeing method color filter uses photolithography to form patterns, so it has higher pattern formation accuracy than other methods of color filters proposed for liquid crystal pull color displays (e.g., printing methods). Moreover, since it is directly dyed with highly saturated organic dye, it also has superior optical properties compared to other types of color filters (for example, printing method, photographic film method, electrodeposition method).

Typical structures of full-color liquid crystal displays using dyed color filters are shown in Figure 12 (kL) and Figure 2Cb). Figure 2 (6) is a plan view, and Figure 2 (6) is a cross-sectional view of this plan view cut along a plane. This structure is an example of a thin film transistor (hereinafter referred to as TIPT) in a liquid crystal display.

In both figures Kb-, 1 to 3 are color filter patterns,
Each one is dyed red, green, and blue.

The size of the pattern, both vertically and horizontally, is equal to the pitch of 1 pixel,
There are no gaps between patterns. The boundaries of the red pattern 1, the green pattern 2, and the blue pattern 5 are arranged so as to pass through the center of the source line 4 on the TPT substrate side and the gate line 5 (K is not shown in FIG. Electrode 6
Patterns 1 to 3 of each color are arranged directly above I and I.

This liquid crystal display performs display in the usual leisted nematic mode. For example, when displaying red t*, by sending a signal to the transparent pixel electrode 6 facing the green pattern 2 and the blue pattern 5 using K or Vl in FIG. 2 (6),
A voltage hZ is applied to the liquid crystal material 8 sandwiched between the transparent common electrodes 7 on the color filter, and the white light 9 is converted to display black. On the other hand, since no signal is sent to the transparent pixel electrode 6' facing the red pattern 1, white light 9 passes through the liquid crystal material 8 in that area and passes through the red pattern 1, making it appear red. Here, 10, 11ij respectively a polarizer and an analyzer, 12
and a 13Fi glass substrate.

In this way, LCD pull color display.

The brightness of the white light in the background is fully utilized for three reasons: the use of polarizing plates, the use of color filters to separate the white light, and the use of liquid crystal as a shutter to control the transmitted light. One screen is dark.

Therefore, dyeing color filters for liquid crystal pull color displays are usually dyed brightly, that is, dyed lightly. As a method of dyeing brightly, transparent method 1
Reduce the thickness and shorten the dyeing time. Lower the dye bath temperature. Various methods can be used, such as lowering the dye concentration in the dye tank.

[Problems and objectives to be solved by the invention] However,
Brightly dyed color filters such as those described above have the disadvantage of being degraded by light, that is, poor light resistance.

FIG. 3 shows the spectral characteristics of the green pattern of a conventional light dyeing color filter. Since the peak transmittance tA of the initial value 14 is high, it is a bright color filter.

However, after the sunlight dew test (approximately 10 days), the left and right baselines ht had significantly increased by 15 orders of magnitude, so when viewed with the naked eye, the color hZ became lighter and appeared dull.

Therefore, the present invention solves these problems.
The objective is to provide cross-cut dyeing color filters suitable for ELL$ full color displays without deteriorating lightfastness.

R Elaborate means to solve problems] The color filter of the present invention is:

α) A color filter in which a transparent organic substance film is colored with a dye; b) The colored portions are arranged in fine regular shapes such as linear stripes or squares.

C) Fine regular transparent or semi-transparent parts are provided between or within each colored part.

d) The area of the transparent or semi-transparent part is 10 to 10% of one colored part.
50 yu shirin? As a countermeasure.

Note that the area of the transparent part of the present invention is 10 to sob of the colored part, preferably 15 to 4Q%, most preferably 20
~30cm.

[Effect]

Before describing embodiments, the present invention will be described in detail.

Figure 4 shows the spectral characteristics of a dyed color filter with a normal dyeing ratio (that is, dyed darker than a lightly dyed color filter for liquid crystal pull color displays), but it is darker than a color filter with the spectral characteristics shown in Figure 3. - Next, it has fallen sufficiently to the baseline hzo +1 of the initial value 16'. Therefore, the baseline hζ increases due to sunlight exposure, and it takes time for it to rise above 0, as shown in the value 17' after one sunlight exposure test.
The spectral characteristics ht hardly change. Of course, this color filter is dark, so it can hardly be used on full-color LCD displays.

Therefore, as shown in FIG. 5, in the dyeing method color filter of the present invention, the initial value of 1 bbs is set in a manner that allows light to pass through the transparent or semi-transparent parts provided between or inside each pattern. It is several inches higher than 16' in the 1g4 diagram over the wavelength range. By appropriately selecting the area of the transparent part, it is possible to control the lift hZ, and it is possible to achieve a brightness K equivalent to that of the conventional light dyeing method color filter shown in FIG.

Specifically, the area of the transparent part is 10% of the colored part (pattern).
While I was busy making ~504, I confirmed that I could get the same brightness as a lightly dyed color filter.

ratio. That is, if the area is less than 10 inches, the effect bZ of the present invention cannot be sufficiently obtained, and if the area is more than 50 inches, the brightness becomes too bright and the saturation decreases significantly.

Since the box, each pattern, and the transparent part have fine regular shapes such as line stripes, squares, and triangles and one circle, each shape hZ is not visible. Here, fine means several hundred micrometers or less.

And the color filter of the present invention shown in Figure @5.

If it is dyed to the same density as the color filter in Figure 4, its light resistance will behave exactly the same as 17/ in Figure 4, as shown by the value 17 after one sunlight exposure test (10 days). 1. The spectral characteristics hardly change.

〔Example〕

Example-1 As a first example, 7t'r cited in the prior art section
The proportionality will be explained by applying the present invention to an FT liquid crystal display.

Figure +W1) is a plan view of the color filter pattern.
One to three patterns of each color are made by coloring gelatin with a dye, and the shape almost matches the shape of the transparent pixel electrode. This shape is not a simple one such as a rectangle or a triangle.
Because they are minute and arranged in a regular manner, they cannot be seen individually by the human eye.

The large angle of the pattern in this example is approximately 150 μm. There is a transparent part 18 between the patterns, and in this embodiment, the area thereof is about 25 inches of the colored part (total area of each color pattern 1 to 3). This belongs to the most preferred area ratio.

The spectral characteristics shown in Figures 1 and 5 are exactly those of this example, and the color filter has become sufficiently bright (initial value 16).
No. 17 showed almost no deterioration after the sunlight exposure test.

I! Figure 1 (6) shows the color filter of this example as TPT.
FIG. 3 is a plan view of the device incorporated into a liquid crystal display. One to three patterns of each color are incorporated so as to closely match the shape of the transparent pixel electrode 6. In this way, only the portion of the liquid crystal that functions as a shutter is colored, increasing efficiency. (not shown), the baseline of the spectral characteristics shown in FIG. Because of the optimal conditions,
This TFT full color display has sufficient brightness and saturation. Special K is effective when external light such as sunlight is used as white light.

Figure 81 (C) Fi, plan view of Figure 1 (b) f A-A'
It is a sectional view of the tension force W toshitomo. Members located above and below the transparent part 18 (polarizer 10, glass substrate 12 and 13° source line 4, liquid crystal material 8, transparent common electrode 1i7° analyzer 11)
) is transparent or colorless and translucent, allowing white light to pass through it efficiently.

The screen display method of the TPT liquid crystal display of this embodiment is the same as that of the conventional example.

Example-2 Example f of f$2 is shown in FIG. The area of the transparent portion 18 in this example is approximately 11c6 of the colored portion, which belongs to the lower limit area of the present invention. This is darker than Example-1, and its color change is higher. If artificial lighting such as a warning light is used as the white light, a certain degree of bright white light can be obtained freely.
There is no particular problem even if the color filter is a little dark.

Example-3 As an example of t43, an example belonging to the upper limit area ratio is a
It is shown in the t7 diagram. In this example, the transparent part 18 is approximately 48% of the colored part.
It's a cloud. It is much brighter than Example 1, and is suitable when relatively dark external light such as indoor light is used as the white light.

Example-4 As a fourth example, transparent portion 18f each color pattern 1 to 3
An example provided inside the is shown in figure at8. In this example, the transparent portion 18 is approximately 16 inches of the colored portion, and the effect is the same as providing a transparent portion between each color pattern.

Examples - Others The color filter of the present invention does not need to be a three-color color filter like the four examples described above, and can be applied to a single color, two colors, or a color filter with four or more colors arranged.
The effect is no different than when it's three colors.

In addition, the color filter of the present invention can be applied not only to TFT liquid crystal displays, but also to liquid crystal displays that apply diode characteristics such as M (metal injected metal), multiplexing liquid crystal displays, solid-state image sensors, and image pickup tubes. Combinations such as hZ are possible.

Furthermore, it is effective not only when used in combination with such a device but also when simply used as a color filter.

〔effect〕

As explained above, according to the present invention, without changing the dyeing density f, an arrangement (pattern) of colored parts with fine regular shapes and the same (fine regular transparent or semi-transparent parts) between or within them can be created. By providing this, it is possible to make the entire color filter brighter without deteriorating the light resistance and because of the light passing through the transparent part.

[Brief explanation of drawings]

FIG. 1(b) is a plan view of a pattern of a dyeing color filter according to a first embodiment of the present invention. Figure 1 (6) is. FIG. 2 is a plan view of a TPT liquid crystal pull color display using the same color filter. FIG. 1(C) is a sectional view of the same. Figure 2&'L) is a plane m of a TPT liquid crystal pull color display using a conventional dyeing method color filter. FIG. 2(6) is a sectional view of the same. Figure 3 is a graph of the spectral characteristics of a conventional light dyeing color filter. Figure 4 is a graph of the spectral characteristics of a normally dyed color filter. 1 [Figure 5 is a spectral characteristic graph of the dyeing method color filter of the present invention. FIG. 6 is a plan view of a pattern of a dyeing method color filter according to the at2 embodiment of the present invention. Figure f$7 is a plan view of the color filter pattern of the same third embodiment. FIG. 118 is a plan view of the color filter pattern of the fourth embodiment. 1... Red pattern 2... Green pattern 3... Blue pattern 16... Initial value (of spectral characteristics) 17...
・(Value after 1 daylight exposure test of spectral characteristics 18...
Above the transparent part

Claims (1)

[Scope of Claims] a) A color filter in which a film of a transparent organic substance is colored with a dye, b) The colored portions are arranged in a fine regular shape such as a line stripe or a square, and c) Each colored portion is colored with a dye. A fine regular transparent or semi-transparent part is provided between or inside, and d) The area of the transparent part or semi-transparent part is 10 to 5 times larger than that of the colored part.
A color filter characterized by being 0%.